In the last few years I’ve discovered a secret that has let me sound a lot more youthful than my actual age without resorting to smaller equipment. I’m sure I used this method years ago to a lesser degree but didn’t know why. I just liked the type of sound I got when I did this in certain registers, but didn’t make a method out of it. I am referring to making the mouthpiece do what you want it to and produce exactly the type of sound you want. As I’ve said myriad times before, when the horn comes from the factory it wants to be a laser-beam loud and a fog-horn soft and it is our job to reverse this; but how? The answer is learning how to use the mouthpiece to make the appropriate sound for every passage you are called upon to play. Once again, how? Specifically, being very systematic about where and how we use our air. Most people think that setting their embouchure in the middle of the mouthpiece will give them the best sound no matter the register. Since almost all of us are downstream players our air will hit the bottom of the cup first and fill the cup before exiting into the throat. This will give us what is referred to as a “dark” sound. A dark sound is a sound that has little fundamental, little overtones and doesn’t project well, especially at soft dynamics’s. The opposite of this sound is what I call a “pure” sound. This is a sound that has a strong fundamental or core, and creates natural overtones or ring and color. This type sound projects well at all dynamics from mezzo-forte down to pianissimo, the most difficult dynamics to project. A pure sound is achieved by a fast moving air stream that goes as directly as possible into the throat of the mouthpiece. This is putting the laser-beam into the dynamics where they belong, from MF down to PP. A good way to think about this air placement is to imagine that there is a plug inserted into the bottom half of the mouthpiece which only lets the air hit the upper half. This will result in a clear, pure sound at the middle and softer dynamics’s. Conversely, to take the laser quality out of the forte and fortissimo dynamics imagine there is a plug blocking the top half of the mouthpiece, moving the airstream down in the mouthpiece. Being a downstream player the air will hit very low in the mouthpiece far away from the throat. This actually makes the mouthpiece sound larger than it is, something beneficial at the louder dynamics.
A word must be said about embouchures in general. I find that people who have a 2/3rd’s upper 1/3rd lower embouchure setting tend to have a harder time getting a pure sound because their air naturally hits too low in the mouthpiece. Rather than advocate changing embouchures which I NEVER do, moving the mouthpiece up or down slightly to direct the air in a certain spot can dramatically affect the quality and purity of sound.
Lets put this theory to the test here. Take a middle A in the bass clef staff, which happens to be the first note of the trombone solo in Mahler’s 3rd symphony. Set the mouthpiece so the air hits as low as possible (moving the mouthpiece up slightly on the embouchure,) then play the note at a forte to fortissimo dynamic. Then move the mouthpiece so the air hits as high as possible in the mouthpiece (moving it down on the embouchure,) then play the same note at a pianissimo dynamic. Those two sounds should be of roughly the same type, just different dynamics because you have reversed the tendency of the horn to be a laser-beam loud and a fog-horn soft. Now reverse that and set the embouchure opposite for those dynamics. It will be a laser-beam loud and a fog-horn soft, something we definitely want to avoid! Additionally this method will help people overcome the common tendency of setting too low for upper register playing, and setting too high for lower register playing, because if you are setting your embouchure in the middle for everything you are probably not hitting the “sweet spot” for the purest sound possible.